11.06

Posted 2020-10-13

package practice;

 

class Person {

        private String name;

        private static int count;

        public Person(){

            count++;

            this.name="NONAME - " + count;

        }

        public Person(String name){

            this.name=name;

        }

        public String getInfo(){

            return "姓名:"+this.name;

        }

    }

    public class DemoOutput {

        public static void main(String args[]) {

            System.out.println(newPerson().getInfo());

            System.out.println(newPerson("A").getInfo());

            System.out.println(newPerson("B").getInfo());

            System.out.println(newPerson().getInfo());

         

    }

};

package practice;

 

class Person1{

    private String name;

    private static int count;

    public Person1(){

        count++;

        System.out.println("产生了"+count+"个实例化对象。");

    }

    public String getInfo(){

        return "姓名:"+this.name;

    }

};

 

public class DemoOutputA {

    public static void main(String args[]){

        new Person1();

        new Person1();

        new Person1();

        new Person1();

        new Person1();

    }

};

package practice;

 

class Person2{

    private String name;

    private int age;

    static String city="A城";

    public Person2(String name,int age){

        this.name=name;

        this.age=age;

    }

    public String getInfo(){

        return"姓名:"+this.name+",年龄:"+this.age+",城市:"+city;

    }

};

 

public class DemoOutputB {

    public static void main(String args[]){

        Person2 per1=new Person2("张三",30);

        Person2 per2=new Person2("李四",31);

        Person2 per3=new Person2("王五",30);

        System.out.println("==========信息修改之前==========");

        System.out.println(per1.getInfo());

        System.out.println(per2.getInfo());

        System.out.println(per3.getInfo());

        System.out.println("==========信息修改之前==========");

        Person2.city="B城";

        System.out.println(per1.getInfo());

        System.out.println(per2.getInfo());

        System.out.println(per3.getInfo());

    }

 

};

 

package practice;

 

class Single{

    private static Single instance=newSingle();

    private Single(){//将构造方法私有化

    }

    public static Single getInstance(){

        return instance;

    }

    public void print(){

        System.out.println("hello world!!!");

    }

};

 

public class DemoOutputC {

    public static void main(String args[]){

        Single s=null;

        s=Single.getInstance();

        s.print();

    }

 

}